Although the present invention is generally applicable to probing any device, the present invention is particularly suited for probing an integrated circuit to test the integrated circuit. As is known, integrated circuits are typically manufactured as a plurality of dice on a semiconductor wafer. FIG. 1 illustrates a typical test system 100 for testing a semiconductor wafer 124. The exemplary test system shown in FIG. 1, includes a tester 102, a test head 118, a probe card 106, and a prober 120.
A semiconductor wafer 124 is placed on a chuck (also commonly referred to as a stage) 114, which typically is capable of movement in the “x,” “y,” and “z” directions. The chuck 114 may also be capable of being rotated and tilted and may be capable of other motions as well. Once the semiconductor wafer 124 is placed on the chuck 114, the chuck is typically moved in the “x,” “y” directions so that terminals on the dice (not shown) of the wafer 124 align with probes 108 on the probe card 106. The chuck 114 then typically moves the wafer 124 upward in the “z” direction, bringing the terminals into contact with the probes 108. One or more cameras 121, 122 may aid in aligning the terminals and the probes and determining contact between the probes 108 and the terminals.
Once the terminals of the dice (not shown) are in contact with the probes 108, a tester 102, which may be a computer, generates test data. The test data is communicated through one or more communication links 104 to a test head 118. The test data is communicated from the test head 118 through interconnections 116 (e.g., pogo pins) to the probe card 106 and finally to the terminals of the dice (not shown) through probes 108. Response data generated by the dice are communicated in reverse direction from the probes 108, through the probe card 106, through interconnections 116, through the probe head 118, through a communication link 104, to the tester 102.
Typically, the terminals on the dice and the probes 108 are relatively small. Regardless of the size of the terminals and probes, however, improved methods and techniques for aligning the terminals and the probes are needed.